1. Field of the Invention
The invention relates to a release mechanism for a high speed circuit breaker.
2. Description of Related Art
A release mechanism is used with a high speed circuit breaker with a roller rotatingly mounted in a mobile contact bridge on an axle. To close the circuit, a jack actuated by a magnet acts on the roller, pressures the contact bridge against a stationary contact, and closes the circuit through the high speed circuit breaker. The necessary contact pressure is also applied by the magnet through the jack to the roller. In a normal disconnection of the high speed circuit breaker the magnet is deactivated and a prestressed disconnect spring also acting on the roller, draws the contact bridge into the disconnect position. The arc appearing in the process is extinguished in a known manner. If, however, a short circuit current flows through the high speed circuit breaker, this normal disconnect requires too much time and a trigger directly actuated by the short circuit current is actuated. This trigger acts on the jack and causes the gear connection between the roller and the jack to be released. The disconnect spring acting on the roller then becomes immediately effective and the contact bridge is drawn rapidly in the disconnect direction.
The trigger acting on the jack, for example, a trigger magnet, must be dimensioned substantially so as to move the jack safely relative to the roller, as there are large counter forces to be overcome. If the trigger is designed somewhat weaker, the disconnect time is increased to unacceptable values.